This application is based upon and claims the benefit of priority from the prior Japanese Patent Applications No. 11-206205, filed Jul. 21, 1999; No. 11-225180, filed Aug. 9, 1999; and No. 11-361155, filed Dec. 20, 1999, the entire contents of which are incorporated herein by-reference.
The present invention relates to a roofing tile used as a roofing material for a building and, more particularly, to a roofing tile having a photovoltaic module for solar-light power generation.
A photovoltaic module for converting solar-light energy into electrical energy is known. A technique of using such a module mounted on a roofing tile used as roofing material for a building is disclosed in, e.g., Jpn. Pat. Appln. KOKAI Publication Nos. 10-88741, 10-115051, and 10-325216.
A photovoltaic module is fixed on a roofing tile main body by the following method. As the first fixing form, a photovoltaic module is directly bonded to the roofing tile main body with an adhesive. The second fixing form is disclosed in Jpn. Pat. Appln. KOKAI Publication No. 11-1999: a roofing tile main body having a recess is used, a photovoltaic module is bonded to the bottom surface of the recess with an adhesive, and the gap between the photovoltaic module and the inner peripheral surface of the recess is filled with a caulking material.
However, an adhesive or caulking material readily degrades. The adhesive or caulking material rapidly degrades especially in, e.g., a rooftop environment where it is exposed to sunbeams and increases its temperature, or open to wind and rain. If the adhesive or caulking material degrades to form cracks, rainwater or dust may enter the gap between the roofing tile main body and the photovoltaic module through the cracks.
Jpn. Pat. Appln. KOKAI Publication No. 10-88741 discloses an arrangement in which a photovoltaic module is stored in a recess of a plain roofing tile, and a through hole communicating with the reverse side of the roofing tile is formed at the eaves-side edge of the plain roofing tile. Generally, of roofing tiles adjacent in the eaves-ridge direction of a roof, the ridge-side roofing tile has its eaves-side edge portion overlapping the ridge-side edge portion of the eaves-side roofing tile. For this reason, rainwater that has entered the recess of the ridge-side roofing tile is discharged to the reverse side of the roofing tile through the through hole, is received by the eaves-side roofing tile, and runs in the eaves direction along the slope of the eaves-side roofing tile.
The gap between the edge portions of the roofing tiles adjacent in the eaves-ridge direction is sometimes jammed with dust or the like. In this case, it is difficult for the roofing tile disclosed in Jpn. Pat. Appln. KOKAI Publication No. 10-88741 to discharge rainwater that has been discharged to the lower side of the roofing tile in the eaves direction. Accordingly, the water may be discharged to the attic side. Hence, the reliability of drainage to the eaves side is poor.
If the through hole is jammed with dust or the like, it is hard to discharge rainwater that has entered the recess to the lower side of the roofing tile main body. When the photovoltaic module has a terminal box on its lower surface, the terminal box is exposed to the rainwater in the recess. This may cause corrosion of the terminal box or failures such as short circuit and earth leakage at the connection portion between the terminal box and an output cable extracted from the terminal box.
In the roofing tile disclosed in Jpn. Pat. Appln. KOKAI Publication No. 10-115051, a photovoltaic module is stored in a recess. The upper surface of the eaves-side edge portion of this roofing tile is formed to be flush with that of the photovoltaic module almost without forming any step therebetween. At the left and right edge portions, the upper surface of the roofing tile projects from that of the photovoltaic module. This prior art describes the arrangement for making rainwater smoothly run on the surface of the roofing tile, though discharge of rainwater that has entered the recess of the roofing tile is not mentioned.
In the roofing tile disclosed in. Pat. Appln. KOKAI Publication No. 10-325216, a photovoltaic module is stored in a recess. The upper surface of the eaves-side edge portion of this roofing tile is formed to be flush with that of the photovoltaic module almost without forming any step therebetween. At one of the left and right edge portions, the upper surface of the roofing tile projects from that of the photovoltaic module. This prior art describes the arrangement for making rainwater smoothly run on the surface of the roofing tile, though discharge of rainwater that has entered the recess of the roofing tile is not mentioned.
Jpn. UM Appln. KOKAI Publication Nos. 62-52610, 1-148417, 4-28524, and 5-3430 disclose techniques of bonding a photovoltaic module to a roofing tile main body and doing waterproof treatment for the peripheral portion of the bonded photovoltaic module using a caulking material. The caulking material fills the gap between the peripheral portion of the photovoltaic module and the inner peripheral surface of the recess of the roofing tile main body in which the module is stored.
In the roofing tile disclosed in each of these prior-art techniques, since the roofing tile main body and photovoltaic module are bonded, the roofing tile main body and photovoltaic module can hardly be separated. For a number of roofing tiles placed on a roof for solar-light power generation, a certain photovoltaic module may require exchange. In this case, only the photovoltaic module requiring exchange cannot be exchanged, and the roofing tile main body itself must be exchanged. This involves difficult operation of temporarily detaching several roofing tiles around the roofing tile to be exchanged.
Jpn. Pat. Appln. KOKAI Publication No. 10-317592 discloses a technique of setting a roofing tile for solar-light power generation (a roofing tile with photovoltaic) using a fixing metal fitting having a clamp portion projecting from a substrate. The fixing metal fitting is fixed at the ridge-side edge portion of the roofing tile. To lap the sheathing roof board with the roofing tile by tile-roofing, the clamp portion of the fixing metal fitting is bent. The bent clamp portion clamps the eaves-side edge portion of the ridge-side roofing tile. However, the roofing tile disclosed in this prior art must be placed while bending the clamp portion of the fixing metal fitting during tile-roofing operation. Hence, laying is cumbersome, and it is difficult to firmly fix the roofing tile only by bending the clamp portion.
It is the first object of the present invention to obtain a roofing tile having a photovoltaic module to generate power, which can discharge rainwater that has entered the recess where the photovoltaic module is stored to the eaves side at improved reliability.
It is the second object of the present invention to obtain a roofing tile having a photovoltaic module to generate power, which can satisfactorily discharge rainwater that has entered the recess, in addition to the first object.
It is the third object of the present invention to obtain a roofing tile having a photovoltaic module to generate power, which can suppress adverse influence on the terminal box of the photovoltaic module due to rainwater that has entered the recess, in addition to the first object of the present invention.
It is the fourth object of the present invention to obtain a roofing tile having a photovoltaic module to generate power, which can easily exchange a photovoltaic module which requires exchange and also can firmly fix the photovoltaic module to the roofing tile main body.
In order to achieve the first object, according to claim 1 of the present invention, there is provided a roofing tile having a photovoltaic module to generate power, which has, at the eaves-side edge portion of a roofing tile main body set tilted on a roof, at least one water discharge portion crossing the eaves-side edge portion and communicating with a recess of the roofing tile main body, in which the photovoltaic module is stored.
In the present invention, the roofing tile main body is formed from an inorganic material such as clay, synthesis resin material, or cement, a metal material, or a composite material thereof. For the photovoltaic module, a structure can be used, in which a transparent electrode layer, a semiconductor layer for performing photoelectric conversion, and a back electrode layer are sequentially stacked, by a thin-film forming technology, on the back surface of a substrate formed from a transparent insulating material such as a transparent glass plate or transparent synthetic resin, and a protective film is coated on the lower surface. The protective layer is used for insulating, waterproofing, and mechanical protection of the layer covered with the protective layer. As the semiconductor layer, an amorphous semiconductor layer can be preferably used. However, the present invention is not limited to this, and a semiconductor layer formed from a single crystal, polycrystalline, or crystallite may be used. In addition, an Si- or compound-based material may be used. Alternatively, a tandem-type photovoltaic module may be used.
The present invention incorporates that the water discharge portion is formed from a ditch. The present invention incorporates that the drain ditch communicates with lower corner portions of the recess. The present invention incorporates that a level of a bottom surface of the drain ditch is not more than that of a bottom surface of the recess.
The present invention also incorporates that the water discharge portion is formed from a tunnel-like passage. The present invention incorporates that the roofing tile further comprises a sealing material continuously provided around the recess to bond a peripheral portion of the photovoltaic module to the recess, and the passage is formed between the water discharge portion and a portion of the sealing material that crosses the water discharge portion. The present invention also incorporates that the passage is formed from an inner hollow of a pipe having two open ends, the pipe being arranged between the sealing material and the water discharge portion. The present invention incorporates that the roofing tile further comprises a catchment ditch having a lower ditch portion extending in a widthwise direction of the roofing tile main body, the lower ditch portion communicating with the passage. The present invention incorporates that the catchment ditch has a pair of side ditch portions connected to two ends of the ditch portion and extending in a ridge-side edge direction of the roofing tile main body.
According to the arrangement of the present invention, rainwater or the like that has entered the recess is discharged in the eaves direction through the water discharge portion crossing the eaves-side edge portion of the roofing tile main body. In this case, the gap between roofing tiles adjacent and overlapping in the eaves-ridge direction is not used as a drainage-way. For this reason, even when the gap is jammed with dust, drainage is not impeded. Hence, the reliability of discharge of rainwater that has entered the recess in the eaves direction improves. In addition, the rainwater that has entered the recess is not discharged to the attic side.
In order to achieve the second object, according to claim 3 of the present invention, there is provided a roofing tile having a photovoltaic module to generate power, characterized in that the eaves-side edge portion has a pair of stopper portions holding lower corner portions of the photovoltaic module, the drain ditch is formed between the stopper portions, and the single drain ditch has a length slightly smaller than a widthwise size of the recess. In order to achieve the second object, according to claim 4 of the present invention, there is provided a roofing tile having a photovoltaic module to generate power, characterized in that the drain ditch is formed from a single ditch, a width of the drain ditch is not less than a widthwise size of the recess, and the recess and the drain ditch are continuous.
According to the arrangement of this present invention, since the single drain ditch is formed widely to extend in the lateral direction of the roofing tile main body, the drain ditch is not jammed with dust. For this reason, the discharge performance for rainwater that has entered the recess in the eaves direction is maintained for a long time.
In order to achieve the third object, according to claim 15 of the present invention, there is provided a roofing tile having a photovoltaic module to generate power, characterized in that the photovoltaic module has, on a reverse surface, a terminal box for extracting a power output from the module, and the roofing tile further comprises a terminal box storing recess formed on a bottom wall of the recess to store the box.
According to the arrangement of this invention, since rainwater that has entered the recess is discharged in the eaves direction through the water discharge portion crossing the eaves-side edge portion of the roofing tile main body, the rainwater that has entered the recess hardly stays in the terminal box storing recess which stores the terminal box. For this reason, the terminal box can be suppressed from being exposed to rainwater in the storing recess.
In order to achieve the fourth object, according to claim 12 of the present invention, there is provided a roofing tile having a photovoltaic module to generate power, characterized by comprising, at the eaves-side edge portion of a roofing tile main body set tilted on a roof, at least one water discharge portion crossing the eaves-side edge portion and communicating with a recess of the roofing tile main body, in which the photovoltaic module is stored, wherein the photovoltaic module is fixed to the roofing tile main body through a fixing jig and nut. The fixing jig has a first end portion having a bent piece overlapping an upper surface of an edge portion of the photovoltaic module and holding the edge portion of the module, and a second end portion to which a bolt extending through the through hole is fixed. The fixing jig is fixed to the roofing tile main body by tightening the detachable nut on the bolt on the reverse side of the roofing tile main body.
The present invention incorporate that the first end portion is holding an eaves-side edge portion of the photovoltaic module. The present invention also incorporates that a levee is formed on the bottom surface of the recess so as to continuously surround a ridge side and left and right sides of the through hole.
According to the arrangement of this invention, when the nut is tightened, the photovoltaic module is pressed against the recess of the roofing tile main body through the fixing jig, and fixed to the roofing tile main body. When the nut is loosened and detached, the photovoltaic module and fixing jig can be detached from the roofing tile main body. Hence, the standalone photovoltaic module can be exchanged. In addition, according to the arrangement having the levee, rainwater that has entered the recess can be prevented by the levee from running into the through hole.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.